JP2922752B2 - Step motor drive controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device for a stepping motor driven by sequentially switching excitation phases.

[0002]

2. Description of the Related Art It is well known that a drive control device for a step motor is widely used in an intake air adjusting device for driving an intake air amount control valve by a step motor. The stepping motor is driven by sequentially switching the phases for exciting the stepping motor based on the determined excitation pattern, and the driving direction is changed by switching the order of the excitation pattern in the forward or reverse direction. ing.

[0003] That is, when the intake air amount control valve is opened by the step motor, the excitation pattern is switched by the required number of times in the forward direction. On the other hand, when the intake air amount control valve is closed, the excitation pattern is switched by the required number of times in the reverse direction. Switch and perform. In general, the switching direction of the excitation pattern and the required number of switching of the excitation pattern are obtained from the magnitude relationship between the actual opening degree of the stepping motor and the target opening degree and the deviation.

[0004] The target opening of the step motor is calculated as the target opening by storing in advance the optimum position of the intake air amount adjusting valve corresponding to the state of the step motor in a memory. On the other hand, the actual opening degree of the step motor is obtained by adding the opening degree at the end of the initialization operation of the step motor as a reference position, and integrating the number of driving (switching) times into the reference position every time the step motor is driven (switching the excitation pattern). Required by

Since the initialization is normally performed at the time of key-off, which is a power-off operation, the drive control device is energized for a predetermined time after the key-off. In the initialization method, as shown in, for example, JP-A-57-26238, the step motor is driven by a predetermined value more than the maximum drive range of the step motor and hits the stopper at the maximum drive position. The end of this drive is defined as the end of initialization, and that position is defined as a reference position. Next, the step motor is driven from the reference position so as to have the target opening at the time of key-off, and the processing at the time of key-off is completed. Thereafter, when a predetermined time has elapsed after the key-off, the power relay is turned off and the power supply is cut off.

At the next key-on, the control is started on the assumption that the actual opening stored in the memory matches the actual opening of the step motor.

[0007]

However, there is a reset period of the microcomputer immediately before the power supply relay is turned off due to the interruption of the power supply, and the output signal of the microcomputer becomes a certain level. The excitation phase also has a specific pattern, and if the excitation phase in the specific pattern is different from the step motor excitation phase set immediately before resetting, the step motor will be driven. As a result, at the next key-on, the opening stored in the memory does not coincide with the actual opening of the step motor. There is a problem that the position is different from the target opening position.

[0008] For this reason, for example, when such a conventional drive control device for a step motor is used for an intake air adjusting device of an internal combustion engine, there is a problem that an error occurs in the flow rate of the intake air.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a drive control device for a step motor which can accurately drive the step motor to a target control position. Aim.

[0010]

According to a first aspect of the present invention, there is provided a drive control apparatus for a stepping motor which initializes a stepping motor in a predetermined sequence when a power supply is stopped, and thereafter drives and holds the stepping motor in a predetermined excitation phase. Means,
The power supply is cut off after a predetermined time from the power supply stop operation, and the power supply is turned off for a reset period immediately after the cutoff.
Power supply control means for stopping the calculation of the control amount, and excitation phase setting means for making the predetermined excitation phase the same as the excitation phase set in the reset period.

According to a second aspect of the present invention, there is provided a stepping motor drive control apparatus according to the first aspect, wherein the excitation phase setting means includes an excitation phase control unit which starts the excitation at the start of the control after the reset period. The phase has a predetermined relationship with the excitation phase during the reset period.

Further, according to a third aspect of the present invention, there is provided a stepping motor drive control apparatus according to the first or second aspect, wherein the control target is an internal combustion engine, and the control amount is an idle speed. Speed control amount,
This is one of the EGR control amount and the purge control amount.

[0013]

According to the drive control device for a step motor according to the first aspect of the present invention, the drive holding means initializes the step motor in a predetermined sequence when the power supply is stopped, and then drives and holds the step motor in a predetermined excitation phase. Further, the power supply control means shuts off the power supply after a predetermined time from the power supply stop operation, and performs a reset immediately after the power supply is shut off.
The calculation of the control amount is stopped over a period . And
Excitation phase setting means prevents the stepping motor from being driven unnecessarily by setting the predetermined excitation phase to be the same as the excitation phase set in the reset period.

Further, according to the drive control apparatus for a step motor according to the second aspect of the present invention, the excitation phase in the reset period and the excitation phase at the start of the control after the reset period have a predetermined relationship.

According to a third aspect of the present invention, the control target is an internal combustion engine, and the control amount is an idle speed control amount, EG.
One of the R control amount and the purge control amount.

[0016]

[Embodiment 1] Hereinafter, an embodiment in which the present invention is applied to an idle speed control device will be described with reference to the drawings. FIG. 1 is a block diagram showing the first embodiment. In FIG. 1, reference numeral 1 denotes an internal combustion engine (engine), and 2 denotes an air flow sensor (hereinafter referred to as AF) provided at an inlet of an intake pipe 7 of the engine 1.
Reference numeral 4 denotes a throttle valve provided in the intake pipe 7. In the intake air passage 8 bypassing the throttle valve 4, an intake air amount control valve 31 driven by the four-phase unipolar step motor 3 is provided. Is provided. Reference numeral 10 denotes a control device, an input circuit 101 for receiving an output signal of the rotation sensor 6 for detecting the number of revolutions of the engine 1 and an output signal of the AFS 2, and a power supply circuit 10 for inputting and outputting power.
2. a microcomputer 103 having a ROM 106 and a RAM 107;
It comprises an output circuit 104 for outputting 02, 203 and 204. Reference numeral 5 denotes a battery as a power supply, 9A denotes a key switch for performing a power supply stop operation, and 9B denotes a power supply relay for shutting off the power supply to the microcomputer 103.

Step motor drive signals 201 and 202
Are output signals 205 of the microcomputer 103
However, since the step motor drive signal 202 is output via the inverting circuit 108, the step motor drive signals 201 and 202 output on / off reverse signals as a result. Step motor drive signals 203 and 20
4 also receives the output signal 206 of the microcomputer 103,
4 is output via the inverting circuit 109, and as a result, the step motor drive signals 203 and 204 are turned on / off.
Outputs the reverse signal.

FIG. 2 shows step motor drive signals 201, 2
2 shows the relationship between 02, 203, and 204 and the intake air amount adjustment valve 31. As shown, the excitation pattern was changed from 1 → 2 → 3 → 4 →
Switching in the forward direction in the order of 1 moves the intake air amount control valve 31 to the open side, and switching the excitation pattern in the reverse direction in the order of 4 → 3 → 2 → 1 → 4 drives the intake air amount control valve 31 to the close side. Is done.

FIG. 3 shows a step motor 3 performed at the time of key-off.
FIG. 7 is a diagram showing an initialization operation of FIG. The power relay 9B is on for a predetermined time after the key-off, and the control device 1
Since power is supplied to 0, initialization is performed during this time. The initialization is started when the key switch 9A is turned off.

First, an opening larger than the maximum driving range is given as a target opening until the intake air amount adjusting valve 31 hits a stopper (not shown), and the excitation pattern is changed from 1 to 2 until the actual opening matches. Switch in the forward direction in the order of → 3 → 4 → 1 and drive to the open side. After the step motor 3 is driven until the actual opening and the target opening coincide with each other, the actual intake air amount adjusting valve 31 is limited by the stopper. At the same time, the target opening is set to the predetermined standby opening at the time of key-off, and the initialization operation ends.

Next, since the standby opening is normally set to the intermediate opening of the maximum driving range, the excitation pattern is changed from 4 → 3 → 2 → 1 → until the actual opening of the intake air amount adjusting valve 31 matches. 4
In the reverse order, and drive to the closing side . The step motor 3 is driven until the actual opening of the intake air amount adjusting valve 31 and the target opening match, and the process at the time of key-off is ended.

After a lapse of a predetermined time, the microcomputer 103 turns off the output signal 207 and turns off the power supply relay 9B.
To turn off the power supply. At this time, the microcomputer 103 is reset for a moment, and the output signals 205 and 206 of the microcomputer 103 are fixed to fixed outputs each time. Therefore, the step motor drive signals 201, 202, 203 and 204 are also set to the excitation pattern 1 in FIG. 4 to a fixed output. Assuming that the excitation phase at this time is the excitation pattern 1 in FIG. 2, the excitation pattern at the end of the key-off process is the excitation pattern 4 in FIG.
2, the intake air amount control valve 31 moves in the opening direction, as shown in FIG.
In the case of the excitation pattern 2 of FIG.
Is driven in the closing direction, and the stepping motor 3 is driven unnecessarily except for the excitation pattern 1 at the time of the end of the key-off process.

Since the excitation of the stepping motor 3 is performed by switching the excitation pattern, no matter how much drive is performed from the predetermined position in the opening direction or the closing direction, the excitation pattern when returning to the initial predetermined position is the pattern before the driving. It is clear that this is the same as Therefore, if the excitation pattern at the time of key-on is determined, the excitation pattern of the standby opening at the time of key-off can also be determined, and these excitation patterns have the same or constant relationship, that is, the excitation pattern at the time of key-on and the excitation pattern at the time of key-off. Can be constant.

However, when the above-described initialization of the step motor 3 is performed, the number of times of driving in the opening direction and the number of times of driving in the closing direction (the number of times of switching the excitation pattern) do not match. In this case, the reference position, for example, The target position of the initialization (intake air) is set so that the deviation between the total number of driving operations in the opening direction and the total number of driving operations in the closing direction from the reference position at key-on is a multiple of 4 which is the number of excitation patterns of the step motor 3. What is necessary is just to determine the number of times the step motor 3 is driven in the opening direction after the amount control valve 31 contacts the stopper.

From the above, the excitation pattern at the time of key-on is used as the excitation pattern at the time of resetting the microcomputer 103, and the amount of contact with the stopper at the time of initialization (the cumulative number of driving from the reference position at the time of key-on in the opening direction and the closing direction) Is set to be a multiple of 4, the excitation pattern at the time of key-off can be the pattern at the time of resetting by the microcomputer 103. The excitation pattern at the time of resetting the microcomputer 103 is known in advance.

If the microcomputer 103 sets the excitation pattern at the time of key-on as the pattern at the time of reset, unnecessary drive of the step motor 3 at the time of key-on can be prevented at the same time. In this case, the control of the intake air amount control valve can be accurately performed.

Next, when it is not known whether the position of the intake air amount adjusting valve 31 at the time of key-on is equal to the standby opening at the time of key-off, such as when the backup power supply is turned off, the excitation at the time of key-on is uniformly performed. The phase cannot be specified. At this time, the initial value at the position at the time of key-on may be replaced with a predetermined value, for example, 0 position, and initialization may be started. When the microcomputer 103 is driven from this initial value to the standby opening at the time of key-off, the microcomputer 103 is reset. If the initialization is performed so as to be the excitation pattern, the microcomputer 103 becomes the reset excitation pattern even when the standby opening is reached after the key-off.

That is, the difference between the number of driving in the opening direction from the 0 position to the standby opening and the number of driving in the closing direction is 4
When the remainder obtained by dividing by 0 is 0, the excitation pattern at the time of key-on can be used as the excitation pattern at the time when the microcomputer 103 is reset.

If the remainder obtained by dividing the deviation from the 0 position to the standby opening by 4 is 1, the excitation pattern at key-on is calculated by subtracting 1 from the reset pattern by the microcomputer 103. And it is sufficient. Similarly, the deviation from the 0 position to the standby opening is 4
When the remainder obtained by dividing by n is n, the excitation pattern at key-on may be an excitation pattern obtained by subtracting n from the pattern at the time when the microcomputer 103 is reset.

With the above-described method, the excitation pattern at the time of key-on and the excitation pattern of the standby opening at the time of key-off can be the same or have a certain relationship therebetween. As described above, in the first embodiment, the engine is the control target of the first aspect, and the microcomputer 103 constitutes the drive holding unit, the power supply control unit, and the excitation phase setting unit of the first aspect.

As will be apparent from the first embodiment, the present invention stipulates that the excitation pattern of the step motor 3 at the standby opening should be defined so as to be the pattern at the time when the microcomputer 103 is reset. The same effect can be obtained by storing the excitation pattern in each position in a memory in the control device in advance and driving the step motor 3 with the excitation pattern corresponding to the opening degree. Further, in the first embodiment, the present invention is applied to the idle speed control device. However, the same effect can be obtained by applying the present invention to an EGR or purge flow rate adjusting device.

[0032]

As is clear from the above description, according to the drive control apparatus for a stepping motor according to the first aspect of the present invention, a predetermined amount of control is performed based on a control amount calculated according to an operation state of a control target. A drive holding unit for initializing the step motor in a predetermined sequence when the power supply is stopped, and then driving and holding the step motor in the predetermined excitation phase in a step motor drive control device that drives the step motor by sequentially switching the excitation phase according to the excitation pattern. Power supply is stopped after a predetermined time from the power supply stop operation, and the power supply is stopped .
The calculation of the above control amount is stopped for the reset period immediately after
Since the power supply control means for stopping the power supply and the excitation phase setting means for setting the predetermined excitation phase to be the same as the excitation phase set in the reset period, the step motor excitation immediately before the reset of the drive control device at the time of the power supply stop operation is provided. the phases can be matched with the excitation phase of the reset period, with step motor unnecessarily driven that no, it is possible to perform drive control of precise step motor, accurately controlled and thus the control object effect that it is possible to it is possible to obtain the.

According to a second aspect of the present invention, there is provided a stepping motor drive control apparatus according to the first aspect, wherein the excitation phase during the reset period and the control start after the reset period are started. Since the excitation phase at the time is set to the predetermined relationship, the same effect as in the first aspect can be obtained, whereby the accurate drive control of the step motor can be performed.

Further, according to the drive control apparatus for a step motor according to claim 3 of the present invention, in the drive control apparatus for a step motor according to claim 1 or 2, the control object is an internal combustion engine. Since the amount is any of the idle speed control amount, the EGR control amount, and the purge control amount, there is an effect that the traveling performance of the vehicle can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a first embodiment;

FIG. 2 is a diagram showing an excitation pattern of a step motor and an operation of an intake air control valve.

FIG. 3 is a diagram illustrating an initialization operation of a step motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Air flow sensor 3 Step motor 4 Throttle valve 5 Power supply 6 Rotation sensor 7 Intake pipe 9A Key switch 9B Power relay 10 Control device 31 Intake air amount control valve 103 Microcomputer

──────────────────────────────────────────────────続 き Continuation of front page (51) Int.Cl. ⁶ identification code FI F02M 69/32 H02P 8/00 302E H02P 8/28 F02D 33/00 318G (58) Investigated field (Int. Cl. ⁶ , DB Name) H02P 8/00-8/42 F02D 21/08 F02D 41/00-41/40 F02M 25/07 550

Claims (3)

(57) [Claims] 1. A stepping motor drive control device that drives a stepping motor by sequentially switching excitation phases in a predetermined excitation pattern based on a control amount calculated according to an operation state of a control target. Sometimes, the step motor is initialized in a predetermined sequence, and thereafter, the driving and holding means for driving and holding the motor in a predetermined excitation phase, and the power supply is shut off after a predetermined time from the power supply stop operation.
During the reset period immediately after the power supply is cut off.
A power supply control means for stopping the calculation of the control amount, and an excitation phase setting means for setting the predetermined excitation phase to be the same as the excitation phase set in the reset period. Control device. 2. The step motor drive control according to claim 1, wherein said excitation phase setting means sets an excitation phase at the start of control after said reset period to a predetermined relationship with an excitation phase during said reset period. apparatus. 3. The step according to claim 1, wherein the control object is an internal combustion engine, and the control amount is any one of an idle speed control amount, an EGR control amount, and a purge control amount. Motor drive control device.